Intravenous drug use is a major vector of HIV transmission. Effective treatments that reduce the use of illicit drugs and to be an effective treatment of drug dependence have been shown to reduce HIV-risk behaviors. We have incorporated HIV-risk measures in all of our clinical trials of substance-abuse treatments. In addition to using standard retrospective questionnaires, we have begun to investigate the collection of HIV-risk-behavior data in real time on handheld electronic diaries. We also plan to incorporate HIV-risk-reduction education on these devices as a component of our mobile-health project